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Investments - Fair Value of Long-Term Available-for-Sale Investments (Detail) - Long-Term Investments [Member] - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale investments	$ 256,855	$ 157,201
Time Deposits and Certificates of Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale investments		48
Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale investments	140,677	75,674
Corporate Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale investments	103,570	64,669
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale investments	605	1,254
U.S. Agency Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale investments	$ 12,003	$ 15,556

X

- Definition

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 320



-SubTopic 10



-Section 25



-Paragraph 1



-Subparagraph (b)



-URI http://asc.fasb.org/extlink&oid=51813488&loc=d3e22054-111558



Reference 2: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 320



-SubTopic 10



-Section 50



-Paragraph 5



-Subparagraph (aa)



-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563



Reference 3: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 320



-SubTopic 10



-Section 45



-Paragraph 1



-URI http://asc.fasb.org/extlink&oid=49167202&loc=d3e26610-111562

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X

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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